The method of discharging pollution for toilet with siphon principle has been widely used, by releasing the water in the water tank, which passes through the communicating vessels, siphonage produces under the action of atmospheric pressure, so as to strengthen blowdown effect. However, enough water is required for completing siphonage. To reduce water consumption, patent No. CN101649640A has disclosed “a pumping drainage device”, arranging a piston tube at the end of the siphon of the toilet, with the piston movement in the piston tube, negative pressure is formed at the end of the siphon, enabling the water in the pipeline to be siphoned rapidly, achieving the purpose of saving water and sewage removing. Due to that the size, mounting position and operational space of a toilet are limited, while the operating strokes of both the piston and cylinder liner are excessive, to enable the piston head to complete a whole working procedure (moving from the top dead center to the bottom dead center), a complicated shifter fork component drag-link mechanism is adopted, giving rise to complicated structure, difficult operation, unclean pumping, low efficiency and other defects, therefore, restricting the popularization and application of the technology of “a pumping drainage device.”